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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />slotted pipe lower section (well screen) to eliminate severe bed load plugging during <br />a severe rainstorm. Alternative C could also be equipped with a similar intake to <br />address sand issues, however, it is not currently proposed. <br /> <br />Water diversion during the winter creates freezing issues for the diversion. <br />By leaving a pond at the intake structure, winter freezing problems are minimized. <br />An occasional fall maintenance program of sediment removal may be required to <br />maintain the pool capacity. This would be more extensive for Alternatives B, D, E, <br />and G than for Alternatives A and F. <br /> <br />The continued ability to divert the water rights decreed at the reservoir site is <br />an important issue. For Alternatives A, B, D, E, F, and G under low flow conditions, <br />the slotted intake pipe would pass the typical 0.5 to 1.0 cfs available for diversion. <br />At higher flow rates, the intake would be designed to perform as a drop inlet to <br />allow the larger flows to enter the top of the intake structure. For Alternative C, <br />the direct diversion of all flows up to the decreed capacity can be made. Should <br />control of sand prove to be a problem, a slotted standpipe intake similar in concept <br />to that proposed for Alternatives A, B, D, E, F, and G can be installed. <br /> <br />Cost Evaluation <br /> <br />Table 11 lists a summary of the costs associated with the project <br />alternatives. Based on the cost comparison, Alternative G is the least expensive at <br />$316,000, in year 2002 dollars. The other alternatives range from $415,000 to <br />$704,000, significantly more expensive than Alternative G. The major cost item for <br />Alternatives B, C, D and E is the grouted riprap. Riprap for these alternatives would <br />be imported from off-site due the lack of hard, durable rock at the site. Grouted <br />riprap would be placed along the outfall channel at and below the dam, on banks <br />and a portion of the channel bottom, to protect the dam and constructed berm from <br />stream erosion. The need for grouted riprap is substantially related to ensuring the <br />constructed berm below the existing dam does not fail and damage the downstream <br /> <br />28 <br />